Fuel regulator for motor temperature conditions



April 22, 1941. L.-H. MESSINGER, JR

FUEL REGULATOR FOR MOTOR TEMPERATURE CONDITIONS Filed Feb. 8, 1938 INVENTOR Mara/e H mas/N652, J72. I

ATTORNEY Patented Apr. 22, 1941 FUEL REGULATOR FOR MOTOR TEMPERA- TUBE CONDITIONS Lester H. Messinger, Jr., Trumbull, Conn, assignmto Messinger Devices, Incorporated, Bridgeport, Conn, a corporation of Connecticut Application February 8, 1938, Serial No. 189,379

10 Claims.

This invention relates to new and useful improvements in carburetors for internal combustion engines and has particular relation to a carburetor including means to facilitate the starting and operation of a cold motor.

The objects and advantages of the invention will become apparent from a consideration of the following detailed description taken in connection with the accompanying drawing wherein a satisfactory embodiment of the invention is shown. However, it is to be understood that the invention is not limited to the details disclosed but includes all such variations and modifications as fall within the spirit of the invention and the scope of the appended claims.

In the drawing: 7

Fig. 1 is a vertical sectional view through a carburetor having the features of the invention applied thereto; and

Fig. 2 is a detail sectional view taken as along the line 22 of Fig. 1.

Referring in detail to the drawing a carburetor of the downdraft type is shown at l although as the description proceeds it will become apparent that the invention is not limited to any particular type or construction of carburetor. Carburetor it includes a float chamber H to which gasoline or other fuel is supplied as through a connection l2, the amount of fuel in chamber H being regulated by a valve I3 controlled by a float l4 having an arm l5 arranged to cause seating of the valve IS on the fuel in chamber l l reaching a predetermined level.

Carburetor I0 is connected with any suitable air cleaner (not shown) as through a tubular connector a portion of which is shown at l6 and the carburetor has a main passage therethrough of which the upper portion l1 admits air from the strainer to a mixing chamber within the length of said main passage and within which is the large Venturi l8 and a smaller Venturi l9. Below the mixing chamber is a throttle valve to be operated in the usual manner.

Fuel from chamber ll moving through a passage 2| enters a hollow needle-like member 22 and about such member is a tube 23 into which fuel may enter at the openings 24 and such tube and member are arranged for the delivery of fuel to the small Venturi [9 from which it is drawn through the annular slot 25 by air rushing through the mixing chamber.

A,passage 26 connects the air admitting passage ll of the carburetor with the upper portion of float chamber H. A plug 21 having a restricted opening therethrough is threaded or otherwise mounted in the passage 26 whereby to materially reduce the capacity thereof although it is to be understood that such plug may be omitted where the capacity of the passage 26 is small.

Owing to the use of an air cleaner together with its connections there is a static suction pressure in the passag I1 and thepurpose of passage 26 is to equalize such pressur in the passage I l and float chamber H whereby to prevent changing the mixture due to restrictions in the air cleaner, etc. Thus the effect of static suction pressure in the mixing chamber is cancelled out due to the same static pressure existing in the float chamber. Therefore, fuel is fed only due to the velocity pressure in the mixing chamber.

Heretofore it has been the custom to mount a choke valve in the air admitting passage I! whereby on closing of said choke Valve the suction pressure in the mixing chamber is increased for the purpose of supplying additional fuel to the engine while it is cold whereby to facilitate starting and running of the engine prior to its reaching a proper operating temperature. The choke valve used closed below the entrance to the passage 26 whereby the static suction pressure above mentioned is maintained constant in the float chamber. Therefore, it will be clear that with a closed choke valve increased static suction in the mixing chamber or Venturi section ofthe carburetor results in additional fuel being drawn to the engine.

According to the present invention the choke valve is omitted and the restricting plug 21 is arranged in passage 25 when necessary. Then the top of the float chamber is tapped as at 28 for the admission of air to the upper portion thereof. Connected with the opening 28 is a tube 29 having an end 30 mounted in a bracket 3| secured to a side of the engine exhaust pipe or manifold 32 as by screws 33.

Associated with the end 30 of pipe 29 is a valve 34 carried by a length-of thermostatic bimetal 35 one end of which is secured to the brackets 3i as by screws 36. The arrangement is such that when the exhaust pipe 32 and thus the engine (not shown) to which such pipe is connected is cold, the valve 3:3 is in open position being spaced from the pipe end 38. When the engine (and thus the exhaust pipe 32) heats up to operating temperature the bimetal member 35 acts to move valve 32 to close the pipe end 30.

Thus when starting the engine if it is cold the valve 34 is in open position. Air is admitted to the upper portion of the float chamber ii and it is noted that preferably the capacity of opening 28 and pipe 29 is much greater than the capacity of the restricted opening through the plug 2?. Therefore while owing to the static suction pressure in the air admitting passage i'l some air will be drawn through the passage 25 the restricted opening through the plug 21 prevents exhaustion of air from the float chamber in the same quantity as it is admitted through tube or pipe 29 and opening 28.

Accordingly while valve 34 is open there is an excess of static pressure in the float chamber over that in the passage I1 and the mixing chamber with the result that there is a tendency to force fuel from the chamber H to the venturi. The absence of the choke valve lowers the suction pressure obtainable in the mixing chamber but the required pressure differential between the float chamber and the mixing chamber is provided by the admitting of sufficient quantities of air to the former. Thus when valve 34 is open an excessive amount of fuel is fed to the engine for starting and operation while cold.

As soon as the engine warms up to operating temperature the valve 3a is closed by action of the bimetal member 351 with the result that no excess of air being admitted to chamber H the pressure condition therein becomes the same as that in the air admitting portion ll of the main passage through the carburetor. At such times the fuel is fed in the usual manner for engine operation.

From the above it will be clear that with the invention applied to a carburetor the necessity for a choke Valve is eliminated. There is no choke valve in the carburetor of the invention to become deranged and interfere with the proper functioning of an engine equipped with the carburetor. The device of the invention is entirely automatic in its operation although it is to be understood that completely automatic operation is not absolutely necessary.

Having thus set forth the nature of my invention, what I claim is:

1. In a carburetor including a float chamber, a mixing chamber, a passage admitting air to the mixing chamber, a passage connecting the upper portion of the float chamber with said air admitting passage anterior to said mixing chamber, a port entering the upper portion of the float chamher and of greater capacity than said second passage, a tube connected at one end with said port and having its other end located adjacent an exhaust gas heated engine portion, a valve operable to close the said other end of said tube, thermal means operable on being heated to move said valve to closed position, and means mounting said thermal means on said exhaust gas heated engine portion.

2. In a carburetor including a fuel chamber, a mixing chamber, a passage admitting air to the mixing chamber, a passage connecting the upper portion of the fuel chamber with said air admitting passage anterior to said mixing chamber, a port entering the upper portion of the fuel chamber and of greater air admitting capacity than said second passage, a valve operable to close said port, a thermal means operable on being heated to move said valve to closed position, and means mounting said thermal means independent of said carburetor in position to be heated by an exhaust gas heated portion of an en- 3. In a downdraft carburetor, a body having a liquid fuel chamber therein, a passage through said body and having an air entrance portion and a lower mixture discharge portion, a venturi in said passage and forming a mixing chamber intermediate said portions, means for supplying fuel to said mixing chamber from said fuel chamber, a pressure balancing passage providing constant communication between the upper portion of said fuel chamber and the air entrance portion of said first passage, temperature controlled means for admitting air to the upper portion of said fuel chamber, said temperature controlled means being of greaterair admitting capacity than the air exhausting capacity of said balancing passage whereby under predetermined temperature conditions to increase the pressure in the fuel chamber over that in the said air entrance portion of the first passage Without changing th velocity pressure in said mixing chamher.

4. In combination, a carburetor including a body having an air passage therethrough, an air cleaner connected with the entrance to said passage, a fuel chamber in said body, a venturi in said passage and forming a mixing chamber therein inwardly of the entrance thereto, means for supplying fuel to said mixing chamber from said fuel chamber, means connecting the en trance portion of said passage with the upper portion of said fuel chamber to create in the latter the sub-atmospheric pressure created in said entrance portion due to the restriction applied by the air cleaner, and temperature controlled means for admitting air to the upper portion of said fuel chamber under predetermined temperature conditions and of greater air admitting capacity than the air exhausting capacity of the connecting means whereby under predetermined temperature conditions to increase the pressure in the fuel chamber over that in said air entrance portion of the air passage.

5. In combination, a carburetor including a body having an air passage therethrough, an; air cleaner connected with the entrance to said passage, a fuel chamber in said body, a venturi in said passage and forming a mixing chamber thereininwardly of the entrance thereto, means for supplying fuel to said mixing chamber from said fuel chamber, means connecting the entrance portion of said passage with the upper portion of said fuel chamber to create in the latter the sub-atmospheric pressure created in said entrance portion due to the restriction applied by the air cleaner, and temperature controlled means for changing toward atmospheric pressure said sub-atmospheric pressure in said fuel chamber under predetermined temperature conditions.

6. In combination, a carburetor including a body having an air passage therethrough, an air cleaner connected with the entrance to said passage, a fuel chamber in said body, a venturi in said passage and forming a mixing chamber therein inwardly of the entrance thereto, means for supplying fuel to said mixing chamber from said fuel chamber, means connecting the entrance portion of said passage with the upper portion of said fuel chamber to create in the latter the sub-atmospheric pressure created in body having an air passage therethrough, an air cleaner connected with the entrance to said passage, a fuel chamber in said body, a venturi in said passage and forming a mixing chamber therein inwardly of the entrance thereto, means for supplying fuel to said mixing chamber from said fuel chamber, means connecting the entrance portion of said passage with the upper portion of said fuel chamber to create in the latter the sub-atmospheric pressure created in said entrance due to the restriction applied by the air cleaner, a port for admitting air to the upper portion of said fuel chamber and of greater air admitting capacity than the air exhausting capacity of said connecting means, and a valve controlling said port.

8. In combination, a down draft carburetor including a body having an air passage therethrough entering the upper end thereof, an air cleaner connected with the entrance to said passage, a fuel chamber in said body, a venturi in said passage and forming a mixing chamber therein below said entrance, a throttle valve in said passage below said mixing chamber, means for supplying fuel to said mixing chamber from said fuel chamber, means connecting the entrance portion of said passage with the upper portion of said fuel chamber to create therein the sub-atmospheric pressure created in the said entrance portion due to the restriction applied by said air cleaner, and temperature controlled means for admitting air to the upper portion of said fuel chamber and of greater air admitting capacity than the air exhausting capacity of the said connecting means whereby under predetermined temperature conditions to increase the pressure in the fuel chamber over that in said entrance portion of said air passage.

9. A carburetor including a float chamber, a mixing chamber, a passage admitting air to the mixing chamber, a passage connecting the upper portion of the float chamber with said air admitting passage, a port entering the upper portion of the float chamber and of greater capacity than said second passage, a tube connected at one end with said port and of greater capacity than said second passage, a valve to close said tube, thermal means controlling opening and closing of said valve, and said thermal means mounted to be affected by the temperature of an engine with which said carburetor is associated.

10. A carburetor including a float chamber, a mixing chamber, a passage admitting air to the mixing chamber, a passage connecting the upper portion of the float chamber with said air admitting passage, a port entering the upper portion of said float chamber and of greater capacity than said second passage, a valve operable to close said port, a thermal means operable on being heated to move said valve to closed position, and means mounting said thermal means independent of the carburetor and in position to be responsive to the engine temperature of an engine associated with the carburetor.

LESTER H. MESSINGER, JR. 

